Compared with the previous electrical communication, the main difference in fiber communication is that it has many advantages: it has high transmission frequency bandwidth, large communication capacity, low transmission loss, long relay distance, thin line diameter, light weight, quartz, metal material saving, reasonable use of resources, strong insulation and anti-electromagnetic interference, and resistance to anti electromagnetic interference. It has the advantages of strong corrosion resistance, strong radiation resistance, good winding property, no electric spark, small leakage, and strong confidentiality. It can be used in special environment.